1. Volcanoes
6.2

2. What happens when a volcano erupts?
The magma in the asthenosphere is under great pressure. Magma rises into the cracks because magma is less dense than the crust.
Hot Magma
Cool Crust

3. As the magma rises toward the surface, less pressure is on the magma
As the magma rises toward the surface, less pressure is on the magma. This allows dissolved gasses to separate out.
During a volcanic eruption, the dissolved gases rush out, carrying the magma with them.
Once the magma reaches the surface and becomes lava, the gases bubble out.
animation of volcano
Dissolved gases
Magma

4. What are the main parts of a volcano?

5. Pipe
A long tube through which magma moves from the magma chamber to Earth’s surface

6. Vent
The opening through which molten rock and gas leave a volcano

7. Lava Flow
The area covered by lava as it pours out of a volcano’s vent

8. Crater
A bowl-shaped area that forms around a volcano’s central opening
Lava collects there

9. Crater
A bowl-shaped area that forms around a volcano’s central opening
Lava collects there

10. Describe the 3 stages of a volcano.
Active (live): volcano that is erupting or has shown signs that it may erupt in the near future.
Dormant (sleeping): volcano that is not currently erupting but may become active in the future.
Extinct (dead): volcano is unlikely to erupt again.

11. Active: Kilauea Name: Kilauea Location: Hawaii
Last eruption: erupting right now
Considered to be the world’s most active volcano

12. Active: Eyjafjallajokull
Name: Eyjafjallajokull
Location: Iceland
Last eruption: April 14, 2010
Caused the shutdown of air traffic across Europe in 2010

13. Name: Fujiyama (Mount Fuji)
Dormant: Fujiyama
Name: Fujiyama (Mount Fuji)
Location: Japan
Last eruption: 1708

14. Location: California, USA
Dormant: Mount Shasta
Name: Mount Shasta
Location: California, USA
Last eruption: about 1810

15. Extinct: Kilamanjaro Name: Mount Kilamanjaro
Location: Tanzania, Africa
Last eruption: 360,000 years ago

16. Last eruption: unknown
Extinct: Olympus Mons
Name: Olympus Mons
Location: planet Mars
Last eruption: unknown

17. Shield Volcano
A wide, gently-sloping mountain made of layers of lava and formed by quiet eruptions
Example: The Hawaiian Islands

19. Cinder Cone
A steep, cone-shaped hill or mountain made of volcanic ash, cinders, and bombs piled up around a volcano’s opening
NO SIDE VENTS!
Example: Sunset crater in Arizona

21. Composite Volcano
A tall, cone-shaped mountain in which layers of lava alternate with layers of ash and other volcanic materials
Example: Mount St. Helens in Washington and Mount Fuji in Japan

23. Types of Volcanoes (simple version)
Shield
Stratovolcano
Cinder Cone
Composite Volcano
Types of Volcanoes (simple version)

24. Relative Size of Volcano Types

26. Name that Volcano Type!

27. Cinder Cone, Mojave Desert, CA

28. View of the NNW flank of Mauna Loa Volcano from the south side of Mauna Kea Volcano, Hawai`i; both are shield volcanoes. The largest volcanoes on Earth are shield volcanoes.

29. Cinder cone at Little Lake, California.

30. Composite Colima Volcano, Mexico.
A stubby andesite lava flow advances 900-1,200 m down the southwest side of Colima Volcano. Lava was first observed in the summit crater on November 20 and began spilling over the crater rim the next day. Colima Volcano is the most historically active volcano in Mexico.

31. Cinder Cone: (Pu`u ka Pele) was erupted low on the southeast flank of Mauna Kea Volcano. The cone is 95 m in height, and the diameter of the crater at the top is 400 m. Hualalai Volcano in background.

32. Composite
Arenal volcano, in Costa Rica

33. Shield volcanoes are among the largest on Earth
Shield volcanoes are among the largest on Earth. The island of Hawaii is made of five overlapping shield volcanoes, of which Mauna Kea is the tallest.